The present invention relates to a process for the preparation of porous products based on cobalt fluoride or lead fluoride.
More specifically, the invention relates to the preparation of products containing lead or cobalt fluorides in the form of a powder having a large specific surface, which are more particularly usable as sorbents for gas purification purposes.
In the case of cobalt fluoride-based products, they can in particular be used for the purification of uranium hexafluoride containing traces of plutonium hexafluoride and neptunium hexafluoride.
Thus, cobalt fluoride is able at between 93.degree. and 230.degree. C. to reduce neptunium hexafluoride and plutonium hexafluoride into solid tetrafluorides, which are retained by the cobalt fluoride-based porous product. A process of this type is described in French Pat. Nos. 2,034,805 and 2,111,730. For this particular use, the cobalt fluoride treatment capacity is in particular dependent on the specific surface of the cobalt fluoride powder used and this treatment capacity increases with the specific surface of the product. It is also important to have powders with a large specific surface.